I wouldn’t worry too much about the “shame” …
Three different names for the same thing:
A post was merged into an existing topic: AA Combat Engineer Tractor (Frog)
The propulsion unit (system) does work on the impellor principle - in that the propellor acts conventionally, but in doing so it pulls water in through the water intakes and the water is then pushed through the dowty cowls, which act to steer the vehicle in the water.
You can call each component or reaction whatever you like, as it appears the hicks in Norfolk have done, but I stand by my description. The water isn’t ‘jetted’ anywhere, its simply pushed (at about 5 - 8 kts - hardly a ‘jet’) through the cowls.
N.B. with the cowls closed as depicted in the previous snap shots, the vehicle would reverse through the water. With the control levers locked (by a pip pin) the default cowl position is closed. There is a handle supposed to be attached to each cowl externally. This was very handy to grab and pull onself up off the floor to mount the vehicle, but its actual function was to enable manual movement of the cowl to enable clearance of debris etc from the outlet.
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Um-hmm
Edit: Water Jet cutting or machining is something completely different,
the keywords ‘propulsion’, ‘cutting’, ‘machining’ et.c. should be used to distinguish between the usages.
The hicks at Jane’s describe it thusly: “It is propelled in the water by two 330 mm Dowty 40/40B water jets which are mounted one either side of the hull” Jane’s Military Vehicles and Ground Support Equipment 1986
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Okay, what do i know…
I do know that the propulsion units are not actual water jets.
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Well, your description of the function was nearly exactly the definition of a water jet as used by boats, i.e. water inlet + some kind of pump which is usually an impeller + an outlet equipped with a steerable nozzle.
A further indication can be derived from the name of the cowls, Dowty.
Dowty propulsion units installed in the Stalwart
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The propulsion unit is not a water jet, it facilitiates the creation of a water jet…
Dear god, can someone please clean this thread up?
Yes, what can I do for you?
Ah!
I see.
Your prayer has now been answered,
the diversion has been giving a topic of its own
since it was indeed beginning to take on life of its own.
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and now for the semantic side of it:
https://www.ansys.com/simulation-topics/what-is-propulsion
An impeller in water jet systems is usually shaped so that the outer edge of the blades fit snugly inside the tube it is mounted in.
Partial view inside a propulsion unit produced by Dowty, the intake side
The other half of the image above, outlet side:
The slats is where the water would get propulsed out from when propulsing in the reverse direction.
Dowty spelled propulsion unit in a very funny way …
Pump-Jet, Water-Jet or Hydrojet: Pump-jet - Wikipedia
Water is pushed out of a nozzle, preferably with some form of steering.
The water can be forced along by various methods, impellers are common but pumps are an option as well.
